According to CBS News, a little girl in Massachusetts wound up with third-degree burns after making homemade slime with water, Elmer’s glue, and sodium borate – sold as Borax. Slime-making was a hobby Kathleen Quinn’s mother encouraged until she realized how it could hurt her child.

“I thought it was great,” Siobhan Quinn told ABC 13. “I encouraged it, bought all the stuff, and then when they were gone, I bought more. She was being a little scientist…(Now), I feel terrible. I feel like the worst mother.”

But Quinn, mother to 11-year-old Kathleen, didn’t realize that such an innocent and educational project could do so much harm. Now she wants to share her story with other parents who presume homemade slime is always safe.

According to CBS News, Borax is safe if it’s properly diluted, but it’s possible for someone to have a strong reaction to it. That’s what may have been the case with Kathleen, who was woken in the middle of the night by a sudden pain in her hands.

Kathleen’s parents rushed her to a hospital, where the little girl was diagnosed with second and third degree burns, likely from extended exposure to Borax. She will recover, but for now has to wear splints on her hands.

Mrs. Quinn told ABC 13 she understands why so many parents think homemade slime is safe. For a while, she did too.

“I’ve had other mothers say, ‘Oh, we’ve made it a million times, it’s fine, nothing happened to my child,'” she said. “We made [the slime] a million times, too, and nothing else happened.”